Automatic feed-upright ore furnace

ABSTRACT

A volatilizing furnace for recovering metals from their ores includes an elongate upright cylindrical retort chamber, means for introducing the ore into the upper end of the retort, and means for withdrawing the ore gangue from the bottom of the retort. A metal vapor collector conduit is coaxially located with the retort and has spirally arranged aperture for collecting metal vapor under transverse channels extending radially outwardly from the conduit across the retort above each of the apertures. The volatilized metal is withdrawn from the upper end of the collector conduit. A furnace surrounds the retort for heating the retort walls to transfer heat to the ore and volatilize the metal.

i United States Patent Jackson et al. Apr. 8, 1975 [5 AUTOMATIC FEED-UPRIGHT ORE 1.222.251 4/i917 Whitton 75/81 x 2.311.648 2/1943 Duncan 75/81 X FURNACE 2,457,552 12/1948 Handwerk et al. 75/88 [76] Inventors: Dennis H. Jackson, 850 W. Osborne Phoemxi 85013; Darrell Primary E.rarizine rGerald A. Dost Zfival, BOX 42, S11v6! Peak, Attorney, Agent or FirmS'ughrue, Rothwell, Mion, 8531 1 Zinn & Macpeak 22 Filed: Nov. 28, 1973 21 A l N 37 ABSTRACT l 1 PP ,8 A volatiliz ing furnace for recovering metals from their Related U.S. Application Data ores includes an elongate upright cylindrical retort [63 continuatiomimpan f Sen 357,767 May chamber, means for introducing the ore into the upper 1973, b d end of the retort, and means for withdrawing the ore gangue from the bottom of the retort. A metal vapor [52] U.S. Cl. 266/17; 75/62; 75/81; Collector n i i oaxially located with the retort 266/24 and has spirally arranged aperture for collecting metal [51] Int. Cl. F27b 1/00 vapor under ransverse channels extending radially [58] Field of Search 75/62, 66, 69-71, outwardly m the conduit across the retort above 75/81, 86, 88, 91; 266/1548, 24 each of the apertures. The volatilized metal is withdrawn from the upper end of the collector conduit. A [56] Reference Cit d furnace surrounds the retort for heating the retort UNITED STATES PATENTS walls to transfer heat to the ore and volatilize the 669.410 3/1901 Guiterman 75/91 x 1,174,464 3/1916 1 Claim, 3 Drawing Figures Agnew 75/91 IHUUITHF AUTOMATIC FEED-UPRlGI-IT ORE FURNACE CROSS REFERENCE TO RELATED APPLICATIONS The present application is a continuation-in-part application of Ser. No. 357,767 filed May 7, 1973, and now abandoned.

BACKGROUND OF THE INVENTION 1. Field of the Invention This invention pertains to apparatus for recovering metals from their ores.

In another aspect, the invention relates to a volatilizing furnace having no moving parts in which the metal compounds present in the ore are decomposed by indirect heating.

2. Prior Art According to one prior art technique for recovering metal from its ore, such as mercury from cinnebar, the ore is comminuted and then roasted to decompose the mercuric sulfide yielding free mercury which is volatilized and separated from the combustion gases by fractional condensation.

In such processes wherein the mercury compounds are decomposed by direct treatment with hot combustion gases, the volume of off-gas is comparatively large, requiring large and expensive mercury condenser apparatus. Prior art attempts to effect the volatilization of mercury by indirect heating have required the use of relatively expensive and complicated furnaces having moving parts or requiring special techniques for withdrawing the mercury vapor and for removing the mercury ore gangue.

SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide an improved metal volatilization furnace having no moving parts, which can extract virtually all of the metal from the ore, and which is of simplified and rugged construction.

It is a further object of the present invention to provide an arrangement whereby the ore will be continuously tumbled while moving downwardly through the furnace in a spiral path without resorting to moving parts but relying solely on a gravity feed.

These and other objects of the invention will be apparent to those skilled in the art from the following detailed description taken in conjunction with the drawings, in which:

FIG. 1 is a cross-sectional view of a volatilizing furnace embodying the present invention;

FIG. 2 is a top view of the furnace of FIG. 1; and

FIG. 3 is a side view of the furnace of FIG. 1.

Although the furnace according to the present invention can be used for the volitilization of many metals, semi-conductors and other elements from their ores the furnace will be described in conjunction with the recovery of mercury from its ore. This is by way of example only and is not to be considered as limiting the scope of the invention.

Briefly, in accordance with the invention, a volatilizing furnace for recovering mercury from its ores is provided, comprising in combination, an elongate upright cylindrical retort chamber, means for introducing comminuted mercury ore into the upper end of the retort and for withdrawing mercury ore gangue from the bottom of the retort. A vertical mercury vapor collector conduit is disposed coaxially within the retort and has a plurality of apertures disposed in spiral paths along the length of the conduit and downwardly opening mercury vapor collector channels extending radially outwardly from the conduit transversely across the retort above each of the apertures for collecting the volatilized mercury and directing it through the apertures into the conduit. The volatilized mercury is withdrawn from the upper end of the conduit for condensation. A furnace surrounds the retort for heating the walls thereof, thus indirectly heating the mercury ore therewithin.

Turning now to the drawings, FIG. 1 illustrates the surrounding furnace 4 constructed of appropriate firebrick. The furnace has an inner wall 5 extending upwardly from the bottom to insulate the steel wall 6 of the cylindrical retort from direct flame. The steel wall 6 of the retort is constructed of heat-resistant alloy, illustratively %/2 inch thick. The dimensions of the retort are not critical and will depend primarily upon the desired capacity of the apparatus. For example, a retort '4' in diameter by 10 feet high with an 8 inch discharge screw for removing ore gangue will handle 50 tons of A inch ground mercury ore per 24 hours.

The mercury ore is fed through the conduits 23 and 24 which open into the top of the retort 6 and moves downwardly as the mercury ore gangue is removed from the bottom of the'furnace through the discharge openings into conduits l2, l3 and 14 and into the screw conveyer 16-17.

Each of the collectors 7a are secured to the conduit 7 above the apertures 7b by welding or other suitable means and extend radially outwardly across the retort chamber in close proximity to the retort wall 6. The collectors 7a are supported further by gusset plates 7c so that the weight of the ore will not bend the collectors downwardly. As the gravity fed ore passes downwardly over the inverted V-shaped collectors 7a the ore will be tumbled and due to the spiral arrangement of the collectors the ore will also be constrained to move in an overall spiral path. Such an action greatly facilitates the decomposition of the mercury compounds and the vaporization of the elemental mercury.

Heat transferred from the furnace section through the walls 6 of the retort decomposes the mercury compounds in the ore to elemental mercury which is vaporized in the retort. The mercury vapor is collected under the concave collectors 7a which extend radially outwardly from the vapor collector conduit 7 transversely across the retort 6. Mercury vapor collected under the concave collector member 7a is conducted through the apertures 7b in the vapor collector conduit 7 and is removed from the upper end into conduit 10 through the opening 10b. Mercury vapor which does not enter the conduit 7 is collected through the openings 10a and 10c which also discharge into the conduit 10. The collected mercury vapor passes through the conduit 10 into appropriate condensers.

Combustion gases pass out of the furnace section through flues 25 and 26 provided with dampers 25a and 26a.

Proper temperature control is maintained by a thermostatic fuel control valve apparatus 18 and by observation of the thermometers la, 2a, 3a and 4a. Air is controllably introduced into the bottom of the retort through the conduits l9 and 20. The apparatus 18 controls the valve 18a in the fuel line 18b leading to burner 18c. The insulating brick liner 5 is provided with a 3,876,189 3 4 flame splitter brick 50 for diverting the flame in opposite directions. Having described the invention, we claim:

In operation, the dwell time of the mercury ore in the l. A volatilizing furnace for recovering an element retort is controlled by the rate of withdral through the from its ore, comprising in combination: screw conveyer 16-17. For most ores, the temperature 5 a. an elongate upright cylindrical retort having at within the retort is controlled at between 800 900F. least one opening in the top thereof for introducing and the dwell time is adjusted to provide for essentially comminuted ore and having at least one opening in complete separation of the mercury values from the the bottom thereof for removing ore gangue; ore. For example, in the 4 X 8 feet retort mentioned b. means for introducing comminuted ore into the above, A inch ore can be suitably treated at a net space 10 upper end of said retort: velocity of approximately 40 pounds per cubic foot per c. means for withdrawing ore gangue from the bothour. tom of said retort;

The same furnace construction can be used for the d. a vapor collector comprising volitilization and recovery of any metal, semii. a stationary vertical vapor collector conduit disconductor or mineral that will vaporize below 2000F. posed concentrically within said cylindrical reand is derived from an ore capable of passing through tort and having a plurality of spirally arranged the furnace in the manner of the ore described above. apertures therein, and

The following elements all have a vapor pressure in ii. a downwardly opening concave vapor collector excess of 10mm at 2000F. and will vaporize below that channel rigidly connected to said stationary vertemperature. However, a number of these elements will tical vapor collector conduit above each of said react with oxygen or water and will require an inert atapertures and extending radially outwardly tomosphere for vaporization. ward said retort for collecting rising vapors and directing said vapors through said apertures to g the interior of said conduit; e. means for withdrawing said vapors from the upper A t' L'th' S l ILQ'IIZ 3: 2: end of said vertical vapor collector conduit; and

Barium Phosphorus Tellufium f. a furnace surrounding said retort for heating the Calcium Potassium Thalllum th f Cesium Rubidium Zinc 8 ereo 

1. A volatilizing furnace for recovering an element from its ore, comprising in combination: a. an elongate upright cylindrical retort having at least one opening in the top thereof for introducing comminuted ore and having at least one opening in the bottom thereof for removing ore gangue; b. means for introducing comminuted ore into the upper end of said retort: c. means for withdrawing ore gangue from the bottom of said retort; d. a vapor collector comprising i. a stationary vertical vapor collector conduit disposed concentrically within said cylindrical retort and having a plurality of spirally arranged apertures therein, and ii. a downwardly opening concave vapor collector channel rigidly connected to said stationary vertical vapor collector conduit above each of said apertures and extending radially outwardly toward said retort for collecting rising vapors and directing said vapors through said apertures to the interior of said conduit; e. means for withdrawing said vapors from the upper end of said vertical vapor collector conduit; and f. a furnace surrounding said retort for heating the walls thereof. 